Beach Renourishment as a Remedy for Beach Erosion 



One way to replace lost beach sand is through beach 

 restoration or beach renourishment. Usually, beach renourishment 

 is done by dredging up sand from offshore and then pumping it 

 onto the beach. Alternately, beach fill material may be 

 transported by truck from another locality and redistributed by 

 bulldozer or other heavy equipment onto the beach. 

 Unfortunately, neither method has proved entirely suitable for 

 turtle nesting beaches, primarily because of problems with sand 

 compaction (Raymond 1984b) . The sand of high energy nesting 

 beaches is usually well-sorted (i.e., it is composed of sand 

 grains which are fairly uniform in size) , and it generally has a 

 low silt-clay component (Mortimer 1981) . Sand dredged from 

 offshore is usually poorly sorted and contains large amounts of 

 silt and clay. Even sand transported from elsewhere often 

 contains more fine material than does the native sand. Moreover, 

 the fill material may become artificially compacted by the earth- 

 moving equipment used to redistribute it (Raymond 1984b) . 



Raymond (1984b) and others in Florida (Fletemeyer 1980) 

 found that the resultant sand compaction can seriously impede the 

 ability of a nesting female to construct a suitable nest. 

 Hatching success may also be reduced if the silt-clay fraction is 

 too high (Mortimer 1981) . 



The possibility of using aragonite sand as beach fill is 

 currently under investigation (J. Miller, pers. comm.). 

 Aragonite is a calcium carbonate sand, and a by-product from a 

 mining operation at Ocean Key in the Bahamas. Its positive 

 attributes are that it can be transported cheaply and at any time 

 of the year. Its suitability as a nesting medium, however, has 

 not yet been demonstrated. There is concern that because of its 

 small grain size it may become compacted. Also, because its 

 reflective properties differ from those of the native sand which 

 it would replace, the possibility exists that its thermal 

 properties also differ. 



More research is needed to determine the cause of compaction 

 during beach restoration, and methods to mitigate it. Alternate 

 ways to renourish beaches need to be developed. Until these 

 problems are solved, nesting beaches should be restored only when 

 absolutely necessary. And then, care must be taken to match the 

 textural characteristics of the fill material as closely as 

 possible to that of the native sand. Obviously, beaches should 

 never be renourished during the turtle nesting season. 



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